1. Field of the Invention
This invention relates generally to pistons for internal combustion engines, and methods of manufacturing the pistons.
2. Related Art
A piston used in internal combustion engines, such as a heavy duty diesel piston or light vehicle duty steel piston, is exposed to high temperatures and harsh conditions during operation, especially along the uppermost surface of the piston which faces a combustion chamber. Exposure to the harsh conditions of the combustion chamber makes the piston susceptible to oxidation, erosion, and coking. Therefore, the piston is typically designed with a cooling gallery beneath the uppermost surface. Cooling oil, or another cooling fluid, is typically contained in the cooling gallery to dissipate heat away from the uppermost surface of the piston as the piston reciprocates in the cylinder bore beneath the combustion chamber. Cooling oil can also be sprayed under the combustion bowl of the piston to dissipate heat.
The piston is also preferably formed of a material capable of withstanding the high temperatures and harsh conditions of the combustion chamber. For example, materials having a high thermal conductivity, hot oxidation resistance, exceptional thermal properties, and resistance to erosion and oil coking are preferred. Unfortunately, such materials are typically expensive and therefore are oftentimes not a practical or economical option.